10 Head-Scratching Facts About Gray Hair


Whether it’s no big deal or a perplexing affront to your vanity, gray hair is a fact of life—and still a bit of a mystery.

1. How Hair Turns Gray

Hair grows in a follicle, a bulb-like tube on your scalp. The average head has 100,000 to 150,000 follicles, each operating independently from the others. Hair in its basic, unpigmented state is white. It gets its color from melanin, a pigment that also determines skin color. Two types of melanin, eumelanin (dark brown or black) and phaeomelanin (reddish yellow), combine to make all the hair colors. One hypothesis for why hair goes gray is that aging slows or stops the hair from accessing the melanin, so it comes out gray, silver, or white instead.

2. Hair May Bleach Itself From The Inside Out

New research reveals that graying may be from a build-up of hydrogen peroxide in the hair cell, which causes the hair to bleach itself on the inside. Cells naturally have a small amount of hydrogen peroxide in them, but it’s kept in check by an enzyme called catalase, which converts the hydrogen peroxide to oxygen and water. As we age, the body produces less catalase, so the hydrogen peroxide builds up and, according to the New York Times, blocks “the normal synthesis of melanin, the natural pigment in hair.” Thus the hair turns gray, giving new meaning to the phrase “peroxide blonde.”

3. Graying Is Caused By Heredity

When you’re born, your genes are already hardwired for when and how your hair will turn gray. This includes premature graying—people who gray before age 30 usually do so because it runs in the family. For most of us, graying starts in middle age. Dermatologists go by the 50/50/50 rule of thumb: by age 50, half the population will have at least 50 percent gray hair—although a worldwide survey showed that number was much lower, with only 6 to 23 percent of people half gray by age 50.

4. Race Is Also A Factor

In a related matter, race also determines when you’re likely to gray. In general, Caucasians gray in their mid-30s, Asians in their late-30s, and African Americans in their 40s.

5. Plucking One Gray Hair Will Not Cause Three To Grow In Its Place

This old wives’ tale is a myth. Each follicle can contain only one hair, and plucking it won’t make it able to produce multiple hairs. Furthermore, what you do to one follicle has no effect on the ones around it. That said, excessive plucking isn’t a good idea—it can damage the follicles and even stop hair production in that area altogether.

6. Stress Probably Plays A Role In Graying

When President Obama went gray his first term in office, was it stress, age, or a combination of both? Scientists aren’t sure. While some researchers say that your genes alone are responsible for gray hair, others say that there seems to be a connection between graying and stress, just no direct link to prove it. In 2011, a study by Nobel Prize winner Robert Lefkowitz discovered that long-term productions of the body’s fight or flight response—the instinctive ability to mobilize energy in response to a threatening situation—can damage your DNA and cause premature aging, including graying hair.

7. Trauma Won’t Make You Go Gray Overnight

Another myth is that a major shock will cause your hair to suddenly turn gray. This is sometimes called the Marie Antoinette Syndrome because the French queen’s hair supposedly turned white the night before she was beheaded. But hair, once grown, doesn’t change color, so waking up with a head of white hair isn’t going to happen. Although there is a very rare condition where all of the colored hairs can fall out, leaving only white hairs behind, the simpler answer is that Marie Antoinette probably just took off her wig.

8. Smoking May Cause You To Prematurely Gray

Multiple studies have linked smoking with premature aging, which includes early graying. In 2013, a study found that there is a significant relationship between smoking and gray hair in people under 30. In fact, “smokers were two and half times more prone to develop PHG” or premature hair graying.

9. Body Hair Also Turns Gray

All your body hair—chest, nose, pubic, etc.—can turn gray. Body hair tends to gray at a different rate than the hair on your head, which is why some men can have gray beards and brown hair, or visa versa. By the way, dyeing gray pubic hair is a thing. 

10. Someday, Research May Lead To A Gray Hair Cure

Scientists in Europe discovered a breakthrough with vitiligo, a disease where skin loses pigment and develops white patches. Like hair, vitiligo is caused by “massive oxidative stress via accumulation of hydrogen peroxide,” causing the skin to bleach itself from the inside out. Researchers have successfully treated the discolored skin and eyelashes of vitiligo patients, which has led some to predict a potential cure for gray hair. But while the idea sounds promising, history is full of tonics and creams claiming to cure gray hair. As far as we know, none of them have worked yet.

Wednesday’s Best Amazon Deals Include Computer Monitors, Plant-Based Protein Powder, and Blu-ray Sets

As a recurring feature, our team combs the web and shares some amazing Amazon deals we’ve turned up. Here’s what caught our eye today, December 2. Mental Floss has affiliate relationships with certain retailers, including Amazon, and may receive a small percentage of any sale. But we only get commission on items you buy and don’t return, so we’re only happy if you’re happy. Good luck deal hunting!

Why Your Christmas Lights Always Get Tangled, According to Science


A Christmas tree isn't a Christmas tree without those pretty colored lights, right? OK, no problem. You stored them in a box marked "Xmas lights" 11 months ago. You know where the box is. Now you just have to open the box, grab the lights, and—

That's where it gets tricky. Unless you're very lucky, or extremely well organized, the lights are likely all tangled up; soon you're down on your hands and knees, struggling to untangle a spaghetti-like jumble. (And it's not just you: A couple of years ago, the British grocery chain Tesco hired temporary "Christmas light untanglers" for the holiday season.) But why are Christmas lights so prone to tangling in the first place—and can anything be done about it?

Why do Christmas lights get tangled in the first place?

There are really two separate problems, explains Colin Adams, a mathematician at Williams College in Williamstown, Massachusetts, and the author of The Knot Book, an introduction to the mathematical theory of knots. First, the cord on which the lights are attached is prone to tangling—just as headphone and earbud cords are (or, in the past, telephone handset cords).

Several years ago, physicists Dorian Raymer and Douglas Smith, then at the University of California, San Diego, did a study to see just how easily cords can get tangled. They put bits of string of various lengths in a cube-shaped box, and then mechanically rotated the box so that the strings tumbled around, like socks in a dryer, repeating the experiment more than 3400 times. The first knots appeared within seconds. More than 120 different types of knots spontaneously formed during the experiment. They also found—perhaps not surprisingly—that the longer the string, the more likely it was to become knotted (few knots formed in strings shorter than 18 inches, they noted). As the length of the string increased, the probability of a knot forming approached 100 percent.

The material that the string (or cord) is made of is important too; a more flexible cord is more likely to tangle than a less flexible one. And while the length of the cord matters, so does its diameter: In general, long cords get tangled more easily than short ones, but a cord with a large diameter will be less flexible, which reduces the risk of knotting. In other words, it's the ratio of length to diameter that really matters. That's why a garden hose can get tangled—it's relatively stiff, but it's also very long compared to its diameter.

But that's not the end of the story. If a cord has a metal wire inside it—as traditional Christmas lights do—then it can acquire a sort of "natural curvature," Jay Miller, a senior research scientist at the Connecticut-based United Technologies Research Center, tells Mental Floss. That means that a wire that's been wrapped around a cylindrical spool, for example, will tend to retain that shape.

"Christmas lights are typically spooled for shipping or packing, which bends metal wire past its 'plastic limit,' giving it natural curvature approximately the size of the spool it was wound around," Miller says. Christmas lights can be even harder to straighten than other wound materials because they often contain a pair of intertwined wires, giving them an intrinsic twist.

And then there's the additional problem of the lights. "Christmas lights are doubly difficult, once things get tangled, because there are all of these little projections—the lights—sticking out of them," Adams says. "The lights get in the way of each other, and it makes it very difficult to pull one strand through another. That means once you're tangled, it's much harder to disentangle."

How do you fix tangled Christmas lights?

What, then, can be done? One option would be for manufacturers to make the cord out of a stiff yet elastic material—something that would more readily "bounce back" from the curvature that was imparted to it while in storage. A nickel-titanium alloy known as Nitinol might be a candidate, says Miller—but it's too expensive to be a practical choice. And anyway, the choice of material probably makes little difference as long as the lights still protrude from the cord. Perhaps the biggest breakthrough in recent years has been the proliferation of LED "rope lights" that don't employ traditional bulbs at all; rather, they use LEDs embedded within the rope-like cord itself. Of course, these can still get tangled up in the manner of a garden hose, but without those pesky protrusions, they're easier to untangle.

A simpler solution, says Adams, is to coil the lights very carefully when putting them away, ideally using something like twist-ties to keep them in place. (Martha Stewart has proposed something similar, using sheets of cardboard instead of twist-ties.)

Meanwhile, the mathematicians have some advice if you find yourself confronted with a hopelessly tangled, jumbled cord: Find one of the "free" ends, and work from there.

"Eventually," Adams assures us, "you will succeed."